Soluble polyesterimide resins

Abstract

Interaction of ethylene glycol with a preformed polyesterimide resin at elevated temperatures forms mixtures homogeneous and clear at room temperature and also soluble in non-polluting solvents, such as monoethers of glycols.

What we claim as new and desire to secure by Letters Patent of the United States is: 
     
       1. A process for preparing a polyesterimide resin which is soluble in non-polluting solvents, such as monoalkyl ethers of a glycol which process comprises: (a) adding ethylene glycol to a preformed polyesterimide formed by reacting under esterimide resin forming conditions a reaction mixture comprising: (I) an imide-group-contributing component selected from the class consisting of (A) both (1) a diamine component and (2) an anhydride component including at least one (a) aromatic carboxylic acid anhydride containing at least one additional carboxylic group, said additional group being esterifiable and substantially non-imidizable, or (b) the corresponding acid thereof containing two imide-forming vicinal carboxylic groups in lieu of the anhydride group,   (B) the carboxy functional polyimide reaction product of said diamine component and said anhydride component, and   (C) mixtures of (A) above and (B) above;     (II) an ester-group-contributing component comprising (D) at least one dihydric alcohol containing two esterifiable hydroxyl groups,   (E) at least one polyhydric alcohol containingat least three esterifiable hydroxyl groups,   (F) at least one lower dialkyl ester of a phthalic acid component selected from the group consisting of terephthalic acid, isophthalic acid, and mixtures of said acids; and (b) heating the mixture of ingredients in (a) at an elevated temperature and for a period of time sufficient to incorporate the ethylene glycol into the polyesterimide resin by transesterification, so that upon cooling to room temperature, a clear, homogeneous resinous composition is obtained which is soluble in the aforesaid monoether of a glycol.       
     
     
       2. The process of claim 1 wherein the diamine component includes at least one aromatic diamine. 
     
     
       3. The process of claim 2 further including the step of removing both the resulting lower alcohol derived from the lower dialkyl ester, and the liberated water of reaction. 
     
     
       4. The process of claim 1 wherein component I above is a mixture of an aromatic diamine and a trimellitic component selected from the group consisting of trimellitic acid, trimellitic anhydride and mixtures thereof; and reaction is continued until at least 50% of the theoretical amount of the lower alcohol derived from the lower dialkyl ester is formed and until at least 50% of the theoretical amount of water of esterificatin of the additional --COO-- group of the trimellitic compound is formed. 
     
     
       5. The process of claim 1 wherein the ratio of the total number of hydroxyl (--OH) groups in the mono-, di-, and polyhydric alcohols to the total number of ester-forming carboxyl (--COO--) groups in (a) the anhydride component and (b) the lower dialkyl ester is more than one --OH group per --COO-- group. 
     
     
       6. The process of claim 5 wherein said ratio is from about 1.05 to about 2.5 --OH groups per --COO-- group. 
     
     
       7. The process of claim 1 wherein said (a) diamine component comprises a diamine selected from the group consisting of 4,4'-methylene dianiline, 4,4'-oxydianiline, and mixtures thereof,   (b) said anhydride component comprises a member selected from the group consisting of trimellitic acid, trimellitic anhydride and mixtures thereof,   (c) said dihydric alcohol comprises ethylene glycol   (d) said polyhydric alcohol is tris(2-hydroxyethyl) isocyanurate, and   (e) said lower dialkyl ester is the dimethyl ester of terephthalic acid.   
     
     
       8. The process of claim 1 wherein the ethylene glycol comprises, by weight, from 2 to 10%, based on the weight of the preformed polyesterimide. 
     
     
       9. The process as in claim 1 wherein a saturated aliphatic monohydric alcohol is selected from the group consisting of n-hexanol, 2-ethylhexanol, n-nonanol, n-decanol, n-dodecanol, 2-butyloctanol, tetradecanol, 2,6,8-trimethylnonane-4-ol, and mixtures thereof, is used in making the preformed polyesterimide. 
     
     
       10. The process of claim 1 wherein the reaction mixture used to make the preformed polyesterimide comprises on a molar ratio (a) from about 0.035 to 0.250 mole of ethylene glycol, (b) from about 0.025 to 0.150 mole of tris(2-hydroxyethyl) isocyanurate, (c) from about 0.030 to about 0.18 mole of dimethyl terephthalate, (D) from about 0.10 to 0.20 mole trimellitic acid, trimellitic anhydride or mixtures thereof, (e) from about 0.050 to 0.100 mole of diamine selected from the group consisting of 4,4'-methylene dianiline, 4,4'-oxydianiline, and mixtures thereof, and (f) from about 1.00 to about 20.00 parts of a saturated aliphatic monohydric alcohol having from 8 to 10 carbon atoms, said amounts being per 100 parts, by weight, of the total weight of the five components (a) through (e). 
     
     
       11. The process of claim 1 wherein the anhydride component comprises a trimellitic compound selected from the group consisting of trimellitic acid, trimellitic anhydride, and mixtures thereof, and a member selected from the group consisting of 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl] propane dianhydride, and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride, the corresponding tetra-acids thereof, and mixtures thereof. 
     
     
       12. A resinous composition comprising a preformed polyesterimide resin interacted with 2 to 10%, by weight, thereof ethylene glycol at elevated temperatures, said composition being homogeneous and clear at room temperature, and soluble at room temperature in a monoalkyl ether of a glycol. 
     
     
       13. A resinous composition comprising a preformed polyesterimide resin interacted with 2 to 10%, by weight, thereof ethylene glycol at elevated temperatures, said composition being homogeneous and clear at room temperature and soluble at room temperature in a monoalkyl ether of a glycol, wherein the preformed polyesterimide is the product of reaction of a mixture of ingredients comprising (I) an imide-group-contributing component selected from the class consisting of (A) both (1) a diamine component and (2) an anhydride component including at least one (a) aromatic carboxylic acid anhydride containing at least one additional carboxylic group, said additional group being esterifiable and substantially non-imidizable, or (b) the corresponding acid thereof containing two imide-forming vicinal carboxylic groups in lieu of the anhydride group,   (B) the carboxy functional polyimide reaction product of said diamine component and said anhydride component, and   (C) mixtures of (A) above and (B) above;     (II) an ester-group-contributing component comprising (D) at least one dihydric alcohol containing two esterifiable hydroxyl groups,   (E) at least one polyhydric alcohol containing at least three esterifiable hydroxyl groups,   (F) at least one lower dialkyl ester of a phthalic acid component selected from the group consisting of terephthalic acid, isophthalic acid, and mixtures of said acids.     
     
     
       14. The resinous product of claim 13 prepared in accordance with the process of claim 7. 
     
     
       15. The product of claim 13 prepared in accordance with the process of claim 10.